(a) Field of the Invention
The present invention relates to a repairing device and a repairing method for a display device.
(b) Description of Related Art
Generally, a liquid crystal display (LCD) device includes a liquid crystal (LC) panel assembly including an upper panel and a lower panel provided with pixel electrodes and common electrodes, and an LC layer with dielectric anisotropy interposed between the upper and lower panels. The pixel electrodes are arranged in a matrix and are electrically connected to switching elements such as thin film transistors (TFTs) to be sequentially applied with a data voltage for a row. The common electrodes cover an entire surface of the upper panel and are supplied with a common voltage. A pixel electrode, a common electrode, and the LC layer form an LC capacitor, which together with a switching element connected thereto is a basic unit of a pixel.
The LCD device displays images by adjusting strength of an electric field applied to the LC layer to control a transmittance of light passing through the upper and lower panels. Additionally, for a color display, color filters representing one of primary colors such as red, green and blue colors are disposed in an area of the common electrode opposite to the pixel electrode.
Meanwhile, during a manufacturing process of the LCD device, several tests are performed and defects detected by the tests are repaired. For example, when display signal lines, etc., are disconnected or shorted, or defects at the pixels occur during the manufacturing process the LCD device, the defects are detected via predetermined tests. Such tests include an array test, a visual inspection (VI) test, a gross test, and a module test, and so on.
The array test is used to determine if disconnection of the display signal lines has occurred by applying predetermined voltages to detect whether output voltages are generated or not before a mother glass is divided into separate cells. The VI test is used to determine if disconnection of the display signal lines has occurred by applying predetermined voltages to view the upper and lower panels after the mother glass is divided into separate cells. The gross test is used to determine image quality and the disconnection of the display signal lines by applying predetermined voltages to view a display state of a screen before mounting driving circuits thereon after combining the lower panel and the upper panel. The module test is to determine an optimum operation of the driving circuits after mounting the driving circuits thereon.
The gross test is performed under similar circumstances to a real driving and also detects inferiority of the pixels in a state of making a background of the screen black. A minority portion of the pixels shines brightly due to existence of alien substances within the LC layer or disconnection or shorts of the display signal lines, which is referred to as a bright pixel or a high pixel. Such a bright pixel or high pixel phenomenon occurs in most display devices including LCD devices.
For repairing a high pixel defect, a light blocking member is coated on an external area of the display devices, which is positioned at an outer surface of the upper panel above the high pixel using a chemical vaporization deposition. However, although light does not leak through a front of the display device, light may leak through sides of the display device. Accordingly, the repair may not be performed perfectly.